Magnetic Proximity Induced Giant Enhancement of Valley Polarization and Zeeman Splitting in WS<sub>2</sub>/Fe<sub>3</sub>GaTe<sub>2</sub> Heterostructures
Wajid Ali, Liuli Yang, Yunfei Xie, Hao Song, Ming Huang, Sajid Ur Rehman, Ziwei Li, Zahir Muhammad, Anlian Pan
Abstract
Substrate engineering offers a powerful approach to tailoring quasiparticle interactions in two-dimensional (2D) materials for valley-quantum devices. Here, a significantly enhanced valley polarization of 67% has been observed in a WS 2 monolayer on a thin Fe 3 GaTe 2 (FGT) layer under far-off resonant excitation at 10 K, which is much higher than that of 16% detected from WS 2 monolayer. This enhancement is attributed to the magnetic proximity effect, which leads to a shorter exciton lifetime in the heterostructure without affecting the valley scattering time. The temperature dependence of valley polarization strongly correlates with the thermomagnetic behavior of the FGT film, suggesting a strong exciton–magnon coupling. Additionally, we observe a valley Zeeman splitting of −5 meV, corresponding to an effective Landé g -factor of −66.03, supported by first-principles calculations. These findings underscore the importance of substrate engineering in modulating intrinsic valley carriers of ultrathin 2D materials, opening new avenues for valleytronic devices.